Who won the Battle of Sekigahara?
Tokugawa Ieyasu's Eastern Army won the Battle of Sekigahara on 21 October 1600, defeating the Western Army in a single day of fighting in a foggy valley in central Japan. The victory made Ieyasu master of Japan and founded the Tokugawa shogunate, which would rule for the next two and a half centuries.3
In a narrow valley in central Japan, on a morning thick with fog, two vast armies of samurai met to decide who would rule a country. Sekigahara lasted a single day, and its outcome shaped Japan for the next two and a half centuries.4
A country up for grabs
The great unifier Hideyoshi had died, leaving a young heir and a council of powerful lords. Two men from his regime, Tokugawa Ieyasu in the east and Ishida Mitsunari in the west, gathered rival coalitions, and all of Japan was drawn toward a single reckoning at the crossroads of Sekigahara.5
Hideyoshi died in September 1598. His son Hideyori was five years old, and Hideyoshi had left the country in the care of a council of five regents, the most powerful of whom was Ieyasu. Ieyasu soon began to act as a ruler in his own right, and Mitsunari, who had served Hideyoshi as one of his senior officials, built a coalition of lords to defend the Toyotomi house.6
In the summer of 1600, Britannica relates, Ieyasu led his army north against Uesugi Kagekatsu, another of the regents, who had defied him; in August Mitsunari and his allies formally denounced Ieyasu, and he turned back west. As the historian Stephen Turnbull stresses, much was settled before the armies met: the long defense of Fushimi Castle near Kyoto, the holding down of Western allies in northern Japan and the Eastern capture of Gifu Castle all worked in Ieyasu's favor. On the rainy evening of 20 October Mitsunari pulled his army out of Ogaki Castle and marched to block the Nakasendo, the inland road from Edo to Kyoto, at the crossroads of Sekigahara.7
The armies in the fog
On the morning of 21 October 1600, tens of thousands of men faced each other in the mist. On paper the Western coalition held a strong position, wrapped around the Eastern army. When the fog lifted and the fighting began, it was ferocious and, for hours, evenly matched.8
The Western army spent the night taking up positions on the hills around the valley floor: Mitsunari on Mount Sasao at the left of the line, Ukita Hideie, Otani Yoshitsugu and Konishi Yukinaga in the center, and Kobayakawa Hideaki, with about 15,600 men, on Mount Matsuo at the right. Some 28,000 men of the Mori clan and its allies stood on Mount Nangu, behind the Eastern army, and Ieyasu set up his first headquarters on Mount Momokubari. The fighting began at about 7:30 a.m., when Ii Naomasa and Matsudaira Tadayoshi took the honor of opening the attack from Fukushima Masanori and fired on Ukita's troops.9
The betrayal
The Western coalition was held together by loyalty that some of its lords did not feel. On a hill sat Kobayakawa Hideaki with a large force, secretly in contact with Ieyasu. At the critical moment he turned his men against his own side, charging down into the Western flank. Other waverers followed him. A well-known story holds that Ieyasu forced Hideaki's hand by having his men fire toward the hill. Several historians now regard it as a later invention: it is missing from records written just after the battle, and recent Japanese research argues that Hideaki changed sides as soon as the fighting began.10
Hideaki's men fell first on Otani Yoshitsugu, a sick general who commanded from a palanquin and had been watching Mount Matsuo with suspicion. Wakisaka Yasuharu and three other commanders at the foot of the hill changed sides at the same moment, and Yoshitsugu's force, attacked from three sides, was destroyed. He took his own life.11
Collapse
The Western army, betrayed from within, folded. What had been a balanced battle became a rout, and by afternoon Ieyasu had won.12
Much of the Western army never fought. Kikkawa Hiroie, at the front of the Mori forces on Mount Nangu, had promised Ieyasu to stay out of the battle, and the troops behind him would not move before he did; the National Park Service records that he excused himself three times on the ground that his men were eating lunch. Shimazu Yoshihiro, with 1,500 to 2,000 men, ignored Mitsunari's calls for help and, once the line broke, cut his way out through the Eastern army and returned home to Satsuma. Ukita and Konishi fled at about 1 p.m. and Mitsunari soon after, and at about 2:30 p.m. Ieyasu held the ceremony of viewing the heads of the enemy dead at his final headquarters.13
What happened to Ishida Mitsunari and the defeated lords?
Mitsunari fled toward Mount Ibuki, was captured and was beheaded in Kyoto on 6 November 1600, together with Konishi Yukinaga. Ieyasu then redrew the map of Japan: he confiscated the lands of the lords he saw as enemies, moved others away from their home regions and rewarded his allies, leaving Hideyori in Osaka Castle with a much smaller domain.14
The settlement became the frame of the new order. The fudai, lords who had already been Tokugawa vassals before the battle, held smaller but strategic domains and could serve in his government; the tozama, lords who submitted to him only after Sekigahara, including some who had fought on his side there, kept larger domains far from the center and were shut out of office. Ieyasu had the emperor appoint him shogun in 1603, and in 1615 his forces destroyed the last Toyotomi loyalists, Hideyori among them, at the siege of Osaka.15
250 years of peace
Sekigahara made Tokugawa Ieyasu the master of Japan. Within a few years he was named shogun, founding a dynasty that would rule from Edo for over 250 years, an age of peace and isolation that shaped modern Japan. One misty morning, one betrayal, and the course of a nation was set.16
How many soldiers fought at Sekigahara, and how many died?
No one knows exactly. Most estimates give each side roughly 80,000 to 90,000 men, and the historian Tetsuo Owada, director of the battlefield museum, speaks of more than 150,000 in all. Casualty figures vary even more widely; the National Park Service puts the dead at about 30,000, more than four times the toll at Gettysburg.17
Even the shape of the battle is debated. Stephen Turnbull, drawing on the Japanese historian Shiramine Jun, notes that the earliest reports by participants placed the fighting at Yamanaka, a village near the crossroads, that the terms Eastern and Western army do not appear in writing until 1698, and that the familiar maps of the deployment go back to one drawn by the Japanese General Staff in 1893. The museum's director also notes that the two army names were not used at the time. If Kobayakawa changed sides at the outset, as this research argues, the battle was far shorter than the classic story of a long, even struggle.18
Can you visit the Sekigahara battlefield today?
Yes. The town of Sekigahara in Gifu Prefecture preserves the camp sites of the main commanders, the two mounds where the heads of the dead were buried, and the grave of Otani Yoshitsugu. The Gifu Sekigahara Battlefield Memorial Museum, opened on the battle's anniversary in 2020, stands on the site of Ieyasu's final headquarters.19
The museum, run by Gifu Prefecture, uses a floor-wide screen, a theater film and an observation room over the valley, and marked hiking and cycling routes follow the camps of seven of the leading commanders. Since 2016 the town has been a sister city of Gettysburg, Pennsylvania, and the museum a sister park of Gettysburg National Military Park, after a World Battlefields Summit at Sekigahara that also brought in Waterloo. For the wider story of the age, see the greatest commanders of feudal Japan, from Oda Nobunaga and his victory at Nagashino to Ieyasu himself.20
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